Heavy rainfall a significant risk to bathing water quality

12 May 2021

Heavy rainfall presents a significant risk to improved bathing water quality, according to a new study from the Environmental Protection Agency.

The report found that the quality of bathing water in Irish beaches improved across the country in 2020, but found that periods of heavy precipitation could quickly lead to higher pollution levels.

The EPA assessment found that 96 per cent of bathing waters in Ireland met or exceeded the minimum quality standard. 111 out of 148 sites were classified as excellent, an increase from 107 in 2019.

Sinead O’Brien, Network Coordinator at Sustainable Water Network (SWAN), welcomed the report and the agency’s recommendation to have year-round monitoring of bathing waters to protect the health of swimmers.

“I think monitoring needs to be swifter and more responsive when there is pollution,” she told The Green News.

“Additionally, increased frequency of this investigative monitoring [is needed] so that sources can be detected and addressed as soon as possible. There also needs to be more transparency around the sources of pollution as soon as it’s known,” she said.

In total, 57 pollution incidents were reported to the EPA during 2020. The most frequent cause of pollution was due to discharges from urban wastewater systems, such as when there is stormwater overflow from wastewater treatment plants.

Ms. O’Brien notes that while wastewater is the leading cause of pollution of bathing waters, “agricultural pollution is a close second. That needs to be highlighted also.”

The report urges Irish Water to make improvements in the operation and management of urban wastewater treatment plants in the cases where these impact on the quality of bathing waters.

Bathing water classifications

Bathing waters are classified in one of four categories: ‘Excellent’, ‘Good’, ‘Sufficient’, or ‘Poor’. Classification is based on an assessment of monitoring data over a four-year period.

The minimum mandatory requirement for bathing waters is for them to be classified as having ‘Sufficient’ quality. Waters that are graded as ‘Poor’ require that management measures be put in place to identify and eliminate the sources of pollution.

‘Poor’ bathing waters pose a health and safety risk to potential swimmers. Poor waters incur the risk of carrying microbiological pollution, which could potentially cause illness such as skin rashes or gastrointestinal problems.

If a pollution incident does occur, local authorities apply a swimming restriction at the bathing water, which stays in place until water sampling shows that the water quality has returned to normal.

The report encourages swimmers to check www.beaches.ie to stay up-to-date on water quality information before they head out.

Story by Thomas Hamilton